1. Field of the Invention
The invention relates to a storage system, and a management method in a storage system, and in particular, relates to a technique for establishing a multi-path to and from a storage subsystem and managing a plurality of business-use computers that send/receive information to/from the storage subsystem.
2. Description of Related Art
A storage apparatus (a storage subsystem) and a host (a host computer) connected to the storage apparatus via a storage area network (SAN) is a known example of a storage system. Between the host and the storage apparatus, there are plural adaptors for connection to the SAN, such as a host bass adaptor (HBA), a channel adaptor (CHA), a fibre channel switch and a hub. These adaptors are connected to one another via a plurality of paths (physical path). A storage apparatus like one with a disk array divides a storage area consisting of a plurality of physical disks into a plurality of logical volumes, and establishes a multi-path system determining paths (access paths) for access from a host to logical volumes by selecting from a plurality of physical paths, arranging multiple access paths to a logical volume, maintaining the access by switching the access paths in the event of a failure, and distributing the access path load by using a plurality of access paths at the same time.
In this situation, when a failure occurs in a multi-path management, access paths relating to the location of the failure will be all switched, so the (Input/Output) traffic in the SAN will significantly changed, and consequently the traffic may be concentrated on a particular adaptor or switch, causing a bottle-neck. Therefore, JP2006-268625 A suggests a multi-path system that perceives possible locations of bottle-necks caused by traffic concentration beforehand and notifies an administrator.
Furthermore, JP2007-72571 A suggests a storage system equipped with a host computer, a storage apparatus providing a logical storage area to the host computer, and a management computer connected to the host computer and the storage device via a network, wherein, when a notice of path failure is sent from the host computer or the storage device to the management computer, the management computer defines a new path for the host computer and the storage device, so that any loss of access path redundancy caused by a port failure in the system can result in the system being automatically restored to a redundant path state.
In related art, it has not been taken into consideration much that host computers (hosts) are added to or removed from a storage system on a daily basis. More specifically, when managing each host by a management computer (management server), where a plurality of host computers (hosts) connected to SAN are management targets, if the management server does not perceive information associated with the addition or removal of hosts connected to SAN, the management computer cannot reliably manage information relating to each host.